1. Field of the Invention
The present invention relates to a multiple-type air conditioning apparatus comprising one outdoor unit and several indoor units.
2. Description of the Related Art
Said multiple-type air conditioning apparatus connects one outdoor unit with several indoor units through several refrigerant tubes and signal conductors.
Said signal conductors are used to send commands and signals related to operation.
To install said air conditioning apparatus in a building, refrigerant tubes must properly be connected between the outdoor unit and several indoor units, and signal conductors must also be properly connected between the outdoor unit and several indoor units.
However, refrigerant tubes may be abnormally connected due to erroneous work, or signal conductors may be abnormally connected due to erroneous wiring.
If any of the above error occurs, the air conditioning apparatus will not function properly. Therefore, it is necessary to carefully check out the connection state of the refrigerant tubes and signal conductors by executing test operations after installing the air conditioning apparatus.
However, the above checkout is very troublesome and errors may be overlooked by human operators.
Therefore, an air conditioning apparatus is developed which automatically checks the connection state between one outdoor unit and several indoor units.
For example, an air conditioning apparatus disclosed in the official gazette of Japanese Patent TOKKOSHO 61-54147, checks the connection state between one outdoor unit 2 and several indoor units 1, 1' by sequentially flowing refrigerant through several indoor units 1, 1' to monitor the temperature change in several indoor units 1, 1'.
In this publication, however, only the method of checking the connection state is disclosed, no concrete control method is disclosed showing the relation between the checking of the connection state and the normal air conditioning operation. Therefore, there may occur an erroneous detection of the connection state.
The air conditioning apparatus disclosed in the official gazette of Japanese Patent JIKKAISHO 63-113843 is equipped with several outdoor units X and Y, in which the outdoor unit X connects with the indoor units A through F and the outdoor unit Y connects with the indoor units G through L.
The air conditioning apparatus checks which outdoor unit an indoor unit outputting the operation command is connected to, X or Y, by monitoring the suction-side pressure of the compressor 1 of the outdoor unit X and that of the compressor 1 of the outdoor unit Y.
However, this air conditioning apparatus cannot check which outdoor unit an indoor unit is connected to, X or Y. Therefore, it is impossible to check the connection state between the outdoor unit X and the indoor units A through F and between the outdoor unit Y and the indoor units G through L.